A mesoscale discussion was issued by the Storm Prediction Center this evening for portions of North Illinois, North Missouri and Southeast Iowa. The discussion made mention of how there was an increasing severe risk through early evening. The discussion above was valid until just after 7 pm CDT. The discussion expired on time. However, there is no watch to replace it. Seeing as how early evening is right about now, it would be a good statement to make in saying that there will likely not be severe thunderstorms if they don't develop by 9:00 PM CDT.
Visible satellite imagery shows a blossoming thunderstorm in Southeast Iowa. That is the only activity in the discussion area. While there are some storms in Central Missouri, those are not within what we will be discussing tonight. Clouds dominate North Illinois into South Wisconsin, back into Iowa and North Missouri.
Radar imagery shows the supposedly crazy storm seen blossoming on the visible satellite imagery in Iowa, but both this radar and the radar operated by our Mobile Storm Track Team (MSTT) indicate the storm is actually very weak. We don't yet have enough information to diagnose why the clouds look so intense on visible satellite, but we will find out.
The image above is of MUCAPE, or Most Unstable CAPE. This was what the SPC used for the mesoscale discussion at the top of the page. We see high values of CAPE in North IL, South IA and North MO.
We will keep watching the radars for further information.